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The Food Chain
July 5, 2000
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Calm seas are deeply appreciated by the SSE team today, as we continue exploration of the Monterey Bay National Marine Sanctuary, moving now from a place along the rim of Soquel Canyon to a finger-like extension of the Monterey Canyon. For several days, Dr. Baldo Marinovic has been looking for krill—and finding them, first using acoustic methods to detect where they have gathered far beneath the surface, and later using fine-mesh nets dragged behind the McArthur at known depths to capture samples.
It is obvious that krill like krill. They tend to get together in huge swarms, like bees or crowds at a circus. Blue whales gliding around the bay have been looking for krill, too. They rely on finding them in great concentrated clouds so in a single gulp they can engulf enough of the tiny creatures to make the effort worthwhile. If whales had to eat krill using techniques that robins use for earthworms—one at a time—it could take years for a whale to get a decent mouthful. As it is, it takes several thousand individual krill-creatures to half-fill one of Baldo’s quart sample jars.
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These tiny crustaceans are called Euphausids, and several species prosper in Monterey Bay and nearby waters. Most abundant, though, seem to be Euphausia pacifica, translucent creatures that appear to be constructed of spun glass. Once plopped in a jar of preservative, their pinkish-crystalline sheen becomes orange-opaque, much like the transformation of a shrimp when cooked. Only their great dark eyes seem unchanged.
Baldo longs to dive deep in the canyon himself and see what whales see when they power their way far below the surface for krill snacks, but there has not been time this season for him to complete pilot training. Next best is instructing someone who has been certified to “drive and dive” about what to look for, and to bring back images with the National Geographic’s special cameras. For three hours, Kip roamed the canyon’s edge in depths as great as 847 feet [258 meters], gliding in and out among the milling masses of krill, returning finally with astonishingly crisp close-up images.
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Gale Mead prepared to take the sub down next, but increasingly brisk winds and rising swell forced us to return to calmer waters just offshore from the Monterey Bay Aquarium. As spectacularly wonderful as that aquarium is, Gale was pleased to dive in the “Big Aquarium”—the ocean itself—and from her vantage point 150 feet [50 meters] underwater, spent hours witnessing one of the Bay’s miracles—acres and acres of squid egg clusters, each sausage-shaped sac crammed with the ingredients for making dozens of miniature squid-lets.
Like krill, certain kinds of squid are critical components in the flow of energy that drives the entire Monterey Bay ecosystem and ultimately, the Pacific Ocean, and the world beyond. Sunlight transformed by microscopic plants into tissue is transformed again when consumed by minute crustaceans who in turn are consumed by larger predators and so on through numerous stages. It takes about two pounds of plants to make about a pound of a fast-growing plant-eater such as a chicken; for beef, about 20 pounds of plants for one pound muscle and bone. The amount of plants needed to produce a pound of carnivore many steps away from sunlight via numerous transformations may be stupendous—thousands of pounds of plants at one end of a food chain leading through many and varied lives enroute to producing one pound of a ten-year-old tuna, shark, or human being.
— Sylvia A. Earle
Project Director
Sustainable Seas Expeditions
[Note: nationalgeographic.com does not research or copyedit dispatches.]